1. Technical Field
The present disclosure relates to substrate structures, and more particularly, to a substrate structure allowing an electronic element to be embedded therein.
2. Description of Related Art
Along with the rapid development of electronic industries, electronic products are developed toward the trend of miniaturization and multi-function. Accordingly, various types of packages have been developed. Generally, electronic elements of sensor elements and camera lenses are packaged to form wire-bonding or COB (Chip on Board) type structures.
FIG. 1 is a schematic partially cut-away perspective view of a conventional camera module. Referring to FIG. 1, the camera module is a wire-bonding type packaging module. The packaging module 1 has a circuit element 10, a holder 14 disposed on the circuit element 10, a packaging body 12 held by the holder 14, an IC electronic element 18 packaged by the packaging body 12, a driving element 13 disposed on the holder 14, and a lens 11 disposed on the driving element 13.
The circuit element 10 is a rigid-flex circuit board having a plurality of electrical contacts 100 and a cable 102 for external connection. The holder 14 is disposed on the circuit element 10 for holding the packaging body 12. The packaging body 12 is used to package the electronic element 18. The packaging body 12 has a plurality of circuit layers (not shown) electrically connected to the electronic element 18. Further, the circuit layers have a plurality of conductive pads 16 that are electrically connected to the electrical contacts 100 of the circuit element 10 through a plurality of bonding wires 19 such as gold wires. The electronic element 18 has a sensing area 18a on an upper surface thereof, and the sensing area 18a is exposed from the packaging body 12 for light sensing. The driving element 13 is a voice coil motor (VCM) disposed on the holder 14. The lens 11 is disposed on the driving element 13 and covers the sensing area 18a of the electronic element 18.
FIG. 1′ is a schematic cross-sectional view of another conventional camera module. Referring to FIG. 1′, the camera module is a wire-bonding type packaging module 1′. The packaging module 1′ has a packaging substrate 10′, a holder 14 and an IC electronic element 18 disposed on the packaging substrate 10′, a transparent element 12′ and a driving element 13 disposed on the holder 14, and a lens 11 disposed on the driving element 13.
The electronic element 18 is electrically connected to the packaging substrate 10′ through a plurality of bonding wires 19 such as gold wires. The holder 14 is disposed on the packaging substrate 10′ through an adhesive 140 and covers the electronic element 18. Further, the holder 14 has a cavity 141. The electronic element 18 has a sensing area 18a on an upper surface thereof, and the sensing area 18a is exposed from the cavity 141 of the holder 14 for light sensing. The transparent element 12′ is made of, for example, glass. The transparent element 12′ is attached to a bottom of the cavity 141 of the holder 14 and covers the sensing area 18a of the electronic element 18. The driving element 13 is a VCM disposed on a wall surface of the cavity 141 of the holder 14. The lens 11 is disposed on the driving element 13 and covers the transparent element 12′.
The packaging modules 1, 1′ have high cost and assembly difficulty due to a large number of components.
Further, a large number of component layers of the packaging modules 1, 1′ make it difficult to reduce the thickness and size of the packaging modules 1, 1′. For example, since the driving element 13 of the packaging module 1 has a great thickness and is bonded to the packaging body 12 through the holder 14, it is difficult to reduce the thickness of the packaging module 1. Furthermore, connecting points (for example, the conductive pads 16) are generally arranged around peripheries of the packaging body 12 and the driving element 13. As such, it is difficult to reduce the size of the packaging module 1. Also, since the holder 14 of the packaging module 1′ is required to have a volume enough to cover the electronic element 18, the size of the packaging module 1′ is difficult to be reduced.
In addition, the bonding wires 19 of the packaging modules 1, 1′ have a certain wire loop, and the holder 14 is required to have a sufficient height to prevent the driving element 13 (or the transparent element 12′) from coming into contact with the bonding wires 19. As such, thinning of the packaging modules 1, 1′ cannot be achieved.
Furthermore, the adhesive 140 between the holder 14 and the packaging substrate 10′ of the packaging module 1′ easily causes an alignment problem and increases the thickness of the packaging module 1′.
Therefore, how to overcome the above-described drawbacks has become critical.